Pancreatic incidentalomas: high rate of potentially malignant tumors.

Background: Pancreatic incidentaloma (PI) is an increasingly common diagnosis that has received little attention. We characterized these tumors and compared them with symptomatic pancreatic tumors (nonincidentaloma [NI]).

Study Design: A retrospective database of 475 consecutive pancreatectomies that were performed from January 1995 to June 2007 at our institution was analyzed. Data for PI and NI patient cohorts were compared.

Results: Sixty-four PIs (13.5%) and 411 NIs (86.5%) were identified; 21% of pancreatic body and tail tumors versus 9% of tumors located in the pancreatic head were incidentally diagnosed (p = 0.001). Twenty-two PIs (34%) versus 278 NIs (67%) were malignant (p < 0.0001), 38 PIs (60%) were premalignant, and the remaining 4 (6%) had little or no risk for malignant progression. Intrapapillary mucinous cystic tumor was the most common diagnosis in the PI group (23.4%, n = 15). Of these, 13.3% (n = 2) were invasive versus 40.6% (n = 15) in the NI group (p = 0.02). Likewise, pathologic features for ductal adenocarcinomas were more favorable in PI versus NI tumors. Overall, PI patients had prolonged median disease-specific survival: 145 versus 46 months (p = 0.001). Median disease-specific survival for PI versus NI patients treated for adenocarcinoma were 22 versus 19 months, respectively (p = 0.4); 5-year disease-specific survival for PI versus NI patients treated for intrapapillary mucinous cystic tumor/mucinous cystadenoma were 94% versus 68%, respectively (p = 0.07).

Conclusions: Operation for PI is common, and a substantial proportion of these lesions might be malignant or premalignant. Resection of these early tumors in asymptomatic individuals is associated with improved survival, as compared with patients with symptomatic disease.